Areas of ground subsurface can become unstable due to a variety of conditions. Subsurface, or underground, instability can be caused by natural phenomena. For example, a ground subsurface area can develop cavities or very loose soil conditions, which can be caused by events such dissolution of limestone or internal erosion of earthen materials or by flooding. Subsurface instability may also be related to man-made conditions. For example, removal of earthen material for constructing a structure such as a road or building and/or pumping well activity may lead to sinkhole formation. Sinkholes can result in damage to and/or collapse of structures such as a road. Another example of subsurface instability is raveling, or separating, of geologic layers that can occur underneath storm ponds. Subsurface instability can also occur in areas around other storm water structures. Such unstable subsurface conditions often require stabilization. Stabilization of subsurface conditions can be particularly critical in areas having predominantly sandy soil.
A conventional approach to stabilizing unstable subsurface conditions is injection of a concrete grout into the unstable area. Concrete grout is often used to stabilize unstable subsurface conditions, such as a sinkhole, in sandy soil. Stabilizing subsurface areas with concrete grout can have disadvantages. For example, hardened concrete can impede normal seepage of water through a repaired subsurface. Concrete can introduce an undesirable processed material, in particular cement, into the environment. Another disadvantage is that subsurface injection of concrete can “grout in” buried utilities or other underground structures that make access to such utilities or structures difficult, if not impossible. In addition, underground injection of concrete can be complicated and involve significant cost.
Thus, there is a need to provide systems and methods for stabilizing subsurface areas while overcoming the disadvantages of injecting concrete grout into such areas.